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Biomedical subjects

R Pfister

Publications and source records attributed to R Pfister.

At least 55 records · Page 3Linked to original sources
PubMed1997

Elevated expression of messenger ribonucleic acid encoding IL-13 in the bronchial mucosa of atopic and nonatopic subjects with asthma.

Local secretion of cytokines by T cells within the bronchial mucosa, with consequent selective eosinophil influx, has been implicated in the pathogenesis of bronchial asthma. The cytokine IL-13 exhibits activities (selective eosinophil vascular adhesion by very late antigen-4/vascular cell adhesion molecule-1 interaction and promotion of IgE synthesis and "T112-type" T cell responses) that may be relevant to this process. We hypothesized that, compared with conditions in control subjects, elevated expression of messenger ribonucleic acid (mRNA) encoding IL-13 is a feature of the bronchial mucosa of both atopic (positive skin prick test result to at least one of a range of common aeroallergens) and nonatopic (negative skin prick test results and serum total IgE concentrations within the normal range) subjects with asthma. With use of a semiquantitative reverse transcriptase-polymerase chain reaction technique, we measured the quantities (relative to beta-actin) of IL-13 mRNA in bronchial mucosal biopsy specimens from atopic and nonatopic subjects with asthma and atopic and nonatopic control subjects. Biopsy specimens from the subjects with asthma, whether the subjects were atopic or nonatopic, had statistically equivalent quantities of IL-13 mRNA relative to beta-actin, and these quantities were significantly elevated compared with those in specimens from both the atopic and nonatopic control subjects (p < or = 0.02 in each case), in which the quantities of IL-13 mRNA relative to beta-actin were also statistically equivalent. The quantities of IL-13 mRNA reflected the numbers of EG2+ eosinophils per unit area of submucosa in the biopsy specimens as determined by immunohistochemistry, which were statistically equivalent in the atopic and nonatopic subjects with asthma and significantly elevated as compared with those in both the atopic and nonatopic control subjects without asthma (p < or = 0.007 in each case). Taking the subjects with asthma as a group, no correlations were observed between the quantities of IL-13 mRNA (relative to beta-actin) and several measures of disease severity. These data are consistent with the hypothesis that IL-13 plays a role in the pathogenesis of both atopic and nonatopic asthma, at least partly through promoting recruitment of eosinophils to the bronchial mucosa, although other factors may be more important in regulating the severity of the disease.

Adult↗
PubMed1997

Upregulation of alpha GM-CSF-receptor in nonatopic asthma but not in atopic asthma.

BACKGROUND: Intrinsic asthma is characterized by an increased number of activated eosinophils and macrophages and an increased expression of the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) in the bronchial mucosa. OBJECTIVE: This study was carried out to investigate the expression of alpha GM-CSF receptor (alpha GM-CSFr) messenger RNA and protein in the bronchial mucosa of patients with intrinsic or atopic asthma and of control subjects and to correlate the expression of alpha GM-CSFr to the number of EG2+ cells (eosinophils) and CD68+ cells (macrophages) and pulmonary function. METHODS: Nineteen patients with stable asthma (9 with atopic and 10 with intrinsic asthma) and 22 normal control subjects (12 atopic and 10 nonatopic subjects) were recruited, and FEV1 (percent predicted) and PC20 were measured before bronchoscopy. Endobronchial biopsy specimens were obtained and examined for membrane-bound alpha GM-CSFr by using in situ hybridization and immunocytochemistry. RESULTS: alpha GM-CSFr mRNA- and protein-positive cells were identified in biopsy specimens from all four groups studied. There was no significant difference in the number of cells expressing alpha GM-CSFr mRNA and protein in patients with atopic asthma compared with atopic and nonatopic control subjects. However, the numbers of alpha GM-CSFr mRNA- and protein-positive cells were significantly higher in nonatopic patients with asthma compared with atopic patients with asthma and atopic and nonatopic control subjects (p < 0.001). In the patients with intrinsic asthma, the number of alpha GM-CSFr mRNA-positive cells per millimeter of basement membrane correlated with numbers of CD68+ cells (r2 = 0.87, p < 0.001) but not with EG2+ cells, and colocalization studies demonstrated that 80% of the cells expressing alpha GMCSFr mRNA were CD68+. The expression of GM-CSF was also significantly increased in patients with intrinsic asthma compared with those with atopic asthma and control subjects (p < 0.05). In addition, in intrinsic asthma, there was a correlation between alpha GM-CSFr mRNA and FEV1 (r2 = 0.61, p < 0.05). CONCLUSION: These results demonstrate that elevated numbers of cells expressing alpha GM-CSFr can be detected in nonatopic asthma but not in atopic asthma and suggest that this increased expression is predominantly macrophage-associated and may play an important pathophysiologic role in intrinsic asthma.

Adult↗
PubMed1997

Enhanced expression of cyclo-oxygenase isoenzyme 2 (COX-2) in asthmatic airways and its cellular distribution in aspirin-sensitive asthma.

BACKGROUND: There are two isoforms of cyclo-oxygenase (COX), namely COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and in blood platelets. The metabolites derived from COX-1 are probably involved in cellular housekeeping functions. COX-2 is expressed only following cellular activation by inflammatory stimuli and is thought to be involved in inflammation. METHODS: The expression of COX-1 and COX-2 isoenzymes has been studied in the bronchial mucosa of 10 normal and 18 asthmatic subjects, 11 of whom had aspirin-sensitive asthma (ASA) and seven had non-aspirin-sensitive asthma (NASA) RESULTS: There was a significant fourfold and 14-fold increase, respectively, in the epithelial and submucosal cellular expression of COX-2, but not of COX-1, in asthmatic patients. There was no significant difference in the total number of cells staining for either COX-1 or COX-2 between subjects with ASA and NASA, but the number and percentage of mast cells that expressed COX-2 was significantly increased sixfold and twofold, respectively, in individuals with ASA. There was a mean fourfold increase in the percentage of COX-2 expressing cells that were mast cells in subjects with ASA and the number of eosinophils expressing COX-2 was increased 2.5-fold in these subjects. CONCLUSION: COX-2-derived metabolites may play an essential part in the inflammatory processes present in asthmatic airways and development of drugs targeted at this isoenzyme may have therapeutic potential in the treatment of asthma. Mast cells and eosinophils may also have a central role in the pathology of aspirin-sensitive asthma.

Adult↗
PubMed1997

Membrane-bound and soluble alpha IL-5 receptor mRNA in the bronchial mucosa of atopic and nonatopic asthmatics.

Eosinophilic inflammation and interleukin-5 (IL-5) expression are characteristic features of the bronchial mucosa in asthma. We have investigated the differential expression of membrane and soluble isoforms of alpha IL-5 receptor (alpha IL-5Rm and alpha IL-5Rs) mRNA in asthmatics and in normal control subjects and examined the correlation between alpha IL-5Rm and alpha IL-5Rs expression and the FEV1 and airway hyperresponsiveness. Nineteen subjects with stable asthma (atopic = 9; intrinsic = 10) and 22 control subjects (atopic = 12; nonatopic = 10) were recruited. Endobronchial biopsies were obtained and processed for in situ hybridization and double-staining techniques. There was a significant increase in the number of cells per millimeter basement membrane expressing mRNA for total, membrane-bound, and soluble alpha IL-5R in asthmatics when compared with that in nonasthmatic control subjects (p < 0.001); 93% of the cells positive for alpha IL-5R mRNA were EG2+ve eosinophils. There was no significant difference in the expression of alpha IL-5Rm and alpha IL-5Rs between the atopic and nonatopic asthmatics. The expression of alpha IL-5Rm and alpha IL-5Rs was also nonsignificantly different between the atopic and nonatopic control subjects. However, in the asthmatic subjects, the number of positive cells expressing mRNA for alpha IL-5Rm inversely correlated with FEV1(r2 = 0.89, p < 0.001), whereas the expression of alpha IL-5Rs mRNA directly correlated with FEV1 (r2 = 0.52, p < 0.001). There were no significant correlations between alpha IL-5R isoforms and the methacholine PC20. These results suggest that alpha IL-5R upregulation and differential regulation of alternatively spliced alpha IL-5R mRNA transcripts may influence the eosinophil response and the accompanying changes in airflow limitation in both atopic and nonatopic variants of chronic asthma.

Adult↗
PubMed1997

Expression of interleukin-5 and granulocyte-macrophage colony-stimulating factor in aspirin-sensitive and non-aspirin-sensitive asthmatic airways.

Increased numbers of eosinophils and mast cells in the bronchial mucosa are characteristic features in subjects with aspirin-sensitive asthma. Interleukin-5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are involved in the activation, maturation, and perpetuation of survival of eosinophils. Immunohistochemical techniques were therefore used to study the expression of IL-5 and GM-CSF on frozen bronchial biopsies from 13 aspirin-sensitive asthmatic (ASA) and 8 non-ASA (NASA) subjects. Aspirin sensitivity was diagnosed by lysine-aspirin inhalation provocation. ASA airways demonstrated a significant 2-fold increase in the total number of submucosal inflammatory cells expressing IL-5 (p = 0.03) and approximate 4- and 2-fold increases in the numbers of mast cells expressing IL-5 and GM-CSF (p = 0.02 and p = 0.04, respectively). There was also a 4-fold increase in the number of eosinophils expressing IL-5 (p = 0.004). These results suggest a central role for the mast cell and eosinophil in regulation of the inflammatory cell infiltrate of ASA airways by secretion of the hemopoietic cytokines IL-5 and GM-CSF.

Adult↗
PubMed1997

Bronchial mucosal expression of the genes encoding chemokines RANTES and MCP-3 in symptomatic atopic and nonatopic asthmatics: relationship to the eosinophil-active cytokines interleukin (IL)-5, granulocyte macrophage-colony-stimulating factor, and IL-3.

Intrinsic (nonatopic) asthma is considered to be a distinct pathogenetic variant of asthma since, unlike extrinsic (atopic) asthma, patients are skin-prick test negative to common aeroallergens and have total serum immunoglobulin E concentrations within the normal range. However both atopic and nonatopic asthma are characterized by chronic inflammation of the bronchial mucosa in which eosinophils are prominent and are believed to be associated with local tissue damage. Therefore, specific eosinophil chemoattractants acting in concert with factors which prolong eosinophil survival may at least partly account for selective eosinophil recruitment to the asthmatic bronchial mucosa. The CC chemokines RANTES and monocyte chemotactic protein 3 (MCP-3) are potent eosinophil chemotactic factors, while the cytokines interleukin (IL)-5, granulocyte macrophage-colony-stimulating factor (GM-CSF), and IL-3 prolong eosinophil survival. We have tested the hypothesis that elevated numbers of cells expressing mRNA for RANTES and MCP-3, as well as IL-5, GM-CSF, and IL-3 are present in bronchial biopsies from atopic and nonatopic asthmatics compared with atopic and nonatopic nonasthmatic controls. The technique of in situ hybridization using 35S-labeled riboprobes was employed to detect mRNA+ bronchial mucosal cells. Compared with controls we observed significant increases in the numbers of cells expressing RANTES and MCP-3, as well as IL-5, GM-CSF, and IL-3 (all P values < 0.001) in atopic and nonatopic asthmatics. These observations support the view that atopic and nonatopic asthma are associated with combined bronchial mucosal expression of CC chemokines (RANTES and MCP-3), together with eosinophil-active cytokines (IL-5, GM-CSF, and IL-3). These cytokines might contribute to the bronchial mucosal accumulation of activated eosinophils in both atopic and nonatopic variants of asthma.

Asthma↗
PubMed1996

Effect of endobronchial aspirin challenge on inflammatory cells in bronchial biopsy samples from aspirin-sensitive asthmatic subjects.

BACKGROUND: The aspirin-induced bronchoconstriction in patients with aspirin-sensitive asthma is caused by cysteinyl leukotriene release. The cellular source of the leukotrienes is unknown. The inflammatory cell infiltrate in bronchial biopsy samples from seven aspirin-sensitive asthmatic (ASA) subjects and eight non-ASA subjects before and after local challenge with lysine aspirin was therefore examined. METHODS: Using flexible bronchoscopy, airway mucosal biopsy samples were taken and lysine aspirin solution was placed directly onto a carina of the contralateral lung. Twenty minutes later a second series of biopsy samples was taken from the site of the local endobronchial lysine aspirin challenge. The biopsy samples were double immunostained with a rabbit polyclonal antibody to the enzyme 5-lipoxygenase and monoclonal antibodies to mast cells (AA1), neutrophils (NP57), macrophages (EBM11), T lymphocytes (anti-CD3), and total (BMK13) and activated eosinophils (EG2). RESULTS: A decrease in both absolute mast cell numbers staining with mast cell tryptase (AA1) and the percentage of mast cells co-immunostaining with 5-lipoxygenase was seen in the ASA patients after lysine aspirin challenge compared with the non-ASA control group. There was also an increase in the numbers of activated eosinophils (EG2) in the ASA subjects compared with the non-ASA group. No changes were observed in the total numbers of macrophages (EBM11), neutrophils (NP57), total eosinophils (BMK13), and T lymphocytes (anti-CD3) after challenge with lysine aspirin. CONCLUSIONS: The decrease in numbers of mast cells staining for tryptase and the increase in activated eosinophils after endobronchial challenge with lysine aspirin may represent degranulation of these cell types, and may be an early event associated with aspirin-sensitive reactions in ASA subjects.

Administration, Topical↗
PubMed1996

Inflammatory cell populations in bronchial biopsies from aspirin-sensitive asthmatic subjects.

The inflammatory cell infiltrate in bronchial biopsies of 12 aspirin-sensitive asthmatic (ASA) subjects and eight non-aspirin-sensitive (non-ASA) control subjects have been compared. Biopsies were taken from a right middle or lower lobe segmental carina using fiberoptic bronchoscopy. The biopsies were snap-frozen in OCT, and sections 5 microns thick were doubled immunostained using a rabbit polyclonal antibody to the enzyme 5-lipoxygenase (5-LO) and with a monoclonal antibody to neutrophils (NP57), macrophages (EMB11), and total (BMK13) and activated eosinophils (EG2), mast cells (AA1), and T-lymphocytes (anti-CD3). There was no significant difference in the total numbers of cells staining for 5-LO between the two groups of subjects. As a percentage of total 5-LO cells, there were significantly more mast cells (12.9 +/- 3.8% versus 3.4 +/- 3.1%; p = 0.039) and total eosinophils (34.7 +/- 9.4% versus 11.1 +/- 3.8%; p = 0.044) and significantly fewer macrophages (23.3 +/- 6.1% versus 39.8% +/- 5.3; p = 0.041) in the bronchial biopsies from ASA subjects as compared with non-ASA patients. The numbers of neutrophils, T-lymphocytes, and activated eosinophils were similar for the two groups. The increased numbers of eosinophils and mast cells identified in the bronchial tissue from aspirin-sensitive asthmatic subjects may be the source of the enhanced cysteinyl leukotriene production observed in these subjects.

Administration, Inhalation↗
PubMed1996

High-affinity IgE receptor (FcepsilonRI)-bearing cells in bronchial biopsies from atopic and nonatopic asthma.

Asthma is characterized by bronchial mucosal inflammation. Although allergen-induced activation of cells binding allergen-specific immunoglobulin E (IgE) through high-affinity receptors (Fc(epsilon)RI) is believed to play some role in asthma, inappropriate synthesis of total or allergen-specific IgE cannot be demonstrated in some ("intrinsic") patients despite the fact that the nature of the bronchial inflammation is similar to that in atopic ("extrinsic") asthmatics. We have studied the numbers and phenotype of Fc(epsilon)RI-bearing cells in bronchial biopsies from 12 atopic and 10 nonatopic asthmatic patients and compared our findings with 10 atopic and 12 nonatopic control subjects using single and double immunohistochemistry. Significantly increased numbers of Fc(epsilon)RI-bearing cells were identified in bronchial biopsies from atopic and nonatopic asthmatics and atopic control subjects when compared with normal controls (p = 0.001, 0.006, and 0.0006, respectively). In asthmatics and atopics the majority of Fc(epsilon)RI-bearing cells were identified as mast cells and macrophages; a much smaller percentage were eosinophils. We conclude that elevated numbers of high-affinity IgE receptor-bearing cells are a feature of bronchial biopsies of asthmatic subjects, irrespective of their atopic status.

Adult↗
PubMed1996

IL-4 and IL-5 mRNA and protein in bronchial biopsies from patients with atopic and nonatopic asthma: evidence against "intrinsic" asthma being a distinct immunopathologic entity.

Intrinsic (nonatopic) asthma is considered to be a distinct pathogenetic variant of asthma since, unlike extrinsic (atopic) asthma, patients with the disease are skin test-negative to common aeroallergens, and have total serum IgE concentrations within the normal range. Nevertheless, the recent demonstration of increased numbers of cells expressing the high-affinity IgE receptor in bronchial biopsies from atopic and nonatopic asthmatic subjects, together with epidemiologic evidence indicating that serum IgE concentrations relate closely to asthma prevalence regardless of atopic status, suggests that IgE-mediated mechanisms may participate in the pathogenesis of both atopic and nonatopic asthma. Furthermore both variants of the disease are associated with bronchial mucosal eosinophilic inflammation. Interleukin-4 (IL-4) is an essential cofactor for IgE synthesis, and there is strong evidence that IL-5 plays a major role in eosinophil accumulation in asthmatic inflammation. For these reasons we compared the expression of IL-4 and IL-5 mRNA and protein product using a semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) amplification, in situ hybridization, and immunohistochemistry in bronchial biopsies from symptomatic atopic and nonatopic asthmatic subjects and atopic and nonatopic controls. The results showed that as compared with controls, biopsies from both groups of asthmatic subjects had increased numbers of IL-4 and IL-5 mRNA copies relative to beta-actin mRNA as detected by RT-PCR. Similarly, in situ hybridization and immunohistochemistry demonstrated increased numbers of cells expressing IL-4 and IL-5 mRNA and protein in asthmatic subjects, irrespective of their atopic status. We conclude that individuals with either atopic or nonatopic asthma show infiltration of the bronchial mucosa with cells expressing Th2-type cytokines, providing further evidence for similarities in the immunopathogenesis of these clinically distinct forms of asthma.

Adult↗
PubMed1995

Development of the Xenopus pronephric system.

The pronephros serves as the embryonic kidney of the lower vertebrates. In this report we describe the development of the pronephric system of Xenopus laevis utilizing scanning electron microscopy and novel monoclonal antibodies that specifically recognize different parts of the pronephros. Antibody 3G8 recognizes the tubules and nephrostomes of the pronephroi only and does not react with the duct. Antibody 4A6 stains only the duct and the nephrostomes. These antibodies thus allow the positive identification of these two intermediate mesoderm derivatives. Both reagents detect antigens expressed some time after the pronephric structures first form and probably represent markers of terminal differentiation. When the tubules and duct first form they are separate structures that can easily be distinguished; the connective tubules have a distinctive organization, the collecting (or common) tubule is broader than other tubules, and the narrow pronephric duct has a specific shape and position. In later stages the collecting tubule and the rostral portion of the duct undergo a considerable amount of convolution, and both contribute to the final coiled tubular body of the pronephros. The ability of 3G8 and 4A6 to distinguish these two elements of the nephric system was used to reexplore classical experiments on the interaction between these two structures during development of the pronephric system. The use of whole-mount analysis has allowed us to examine large numbers of embryos from different stages and dissected in a variety of planes. These experiments demonstrate the dynamic nature of the intermediate mesoderm and indicate that although the pronephros may be specified by mid-neurula stages, patterning is not complete until tailbud stages.

Animals↗
PubMed1995

Endocrine ophthalmopathy in a patient under continuous immunosuppressive therapy after cardiac transplantation.

We present the case of a female patient who has been on immunosuppressive therapy consisting of cyclosporin A and prednisolone for 9 years because of heterotopic (auxiliary) heart transplantation in 1984. In 1992 the patient developed Graves' disease followed by endocrine ophthalmopathy class IV 1 year later. To our knowledge this is the first report on Graves' disease with subsequent severe endocrine ophthalmopathy in a patient under immunosuppressive treatment with cyclosporin A and prednisolone in doses that effectively prevent heart transplant rejection. Prednisolone, which is used as a first line treatment of endocrine ophthalmopathy, and cyclosporin A, both inhibit T cell function. However, in this patient they were not effective in preventing the development of Graves' disease with subsequent endocrine ophthalmopathy, both of which are autoimmune diseases.

Adult↗
PubMed1994

Screening for sinus disease in patients with asthma: a computed tomography-controlled comparison of A-mode ultrasonography and standard radiography.

BACKGROUND: Paranasal sinus disease and bronchial asthma are frequently associated. Patients with asthma often have chronic inflammatory changes of the paranasal mucosa rather than acute bacterial sinusitis. Our aim was to compare the rankings of A-mode ultrasonography and standard radiography as routine screening procedures in the diagnostic workup of these patients. METHODS: We compared the evaluation of the maxillary sinuses by A-mode ultrasonography and standard radiographs. Computed tomography served as a gold standard in 19 patients with asthma who had no history of sinus surgery. RESULTS: Computed tomography showed at least some minimal mucosal thickening in any of the paranasal sinuses in 74% and of the maxillary sinuses in 61% of the patients. Compared with the results of computed tomography, plain-view radiography gave a specificity of 86.7% for the maxillary sinuses. Although all cases of severe mucosal thickening were detected, sensitivity for minimal mucosal hyperplasia was low, at 52.2%. In contrast, A-mode ultrasonography demonstrated a sensitivity of 70% but a specificity of only 22%. CONCLUSIONS: Even symptom-free patients with asthma show a high prevalence of at least limited mucosal thickening in the paranasal sinuses. Acute sinusitis is not a common finding. A-mode ultrasonography does not allow sufficient evaluation of this mucosal hyperplasia and is therefore not suitable for initial screening in these patients. It may prove helpful as a follow-up in selected patients with known anatomic characteristics, however, especially when antral fluid is involved. For routine screening in patients with asthma, a conventional Waters' view radiograph should be used in conjunction with direct visualization of the ostial-meatal area by fiberoptic or rigid rhinoscopy. This combination provides information about the degree of mucosal hyperplasia as well as mucosal inflammation and secretion.

Adult↗
PubMed1994

Water, energy and early postnatal growth in preterm infants.

Non-invasive methods, including stable isotope techniques, indirect calorimetry, nutritional balance and skinfold thickness, have given a new insight into early postnatal growth in neonates. Neonates and premature infants in particular, create an unusual opportunity to study the fluid and metabolic adaptation to extrauterine life because their physical environment can be controlled, fluid and energy balance can be measured and the link between metabolism and the energetics of their postnatal growth can be assessed accurately. Thus the postnatal time course of total body water, heat production, energy cost of growth and composition of weight gain have been quantified in a series of "healthy" low-birth-weight premature infants. These results show that total body water is remarkably stable between postnatal days 3-21. Energy expenditure and heat production rates increase postnatally from mean values of 40 kcal/kg/day during the first week to 60 kcal/kg/day in the third week. An apparent energy balance deficit of 180 kcal/kg can be ascribed to premature delivery. The cost of protein metabolism is the highest energy demanding process related to growth. The fact that nitrogen balance becomes positive within 72 h after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism during early postnatal growth: skinfold thickness, dry body mass and fat decrease, while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches statural growth. The goals of the following review are to summarize data on total body water and energy metabolism in premature infants and to discuss how they correlate with physiological aspects of early postnatal growth.

Body Composition↗
PubMed1992

Studies on the developmental cycle of Trichospirura leptostoma (Nematoda: Thelaziidae). Experimental infection of the intermediate hosts Blatella germanica and Supella longipalpa and the definitive host Callithrix jacchus and development in the intermediate hosts.

The cockroaches Blatella germanica and Supella longipalpa can act as intermediate hosts of Trichospirura leptostoma as demonstrated by experimental infestation. The parasite developed from the embryonated egg into the infective larval stage (L3) in cockroaches within 5-6 weeks. After experimental infection of marmosets (Callithrix jacchus), eggs were first found in faecal samples (prepatency) at 8-9 weeks post-infection. Patency lasts about 2 years. Despite the presence of living adult worms in the marmosets' pancreas, no additional eggs were observed in their faeces after the patent period.

Animals↗
PubMed1991

"Neonatal adaptation of energy and protein metabolism".

During the last decade, the development of "bedside" investigative methods, including indirect calorimetry, nutritional balance and stable isotope techniques, have given a new insight into energy and protein metabolism in the neonates. Neonates and premature infants especially, create an unusual opportunity to study the metabolic adaptation to extrauterine life because their physical environment can be controlled, their energy intake and energy expenditure can be measured and the link between their protein metabolism and the energetics of their postnatal growth can be assessed with accuracy. Thus, relatively abstract physiological concepts such as the postnatal timecourse of heat production, energy cost of growth, energy cost of physical activity, thermogenic effect of feeding, efficiency of protein gain, metabolic cost of protein gain and protein turnover have been quantified. These results show that energy expenditure and heat production rates increase postnatally from average values of 40 kcal/kgxday during the first week to 60 kcal/kgxday in the third week. This increase parellels nutritional intakes as well as the rate of weight gain. The thermogenic effect of feeding and the physical activity are relatively low and account only for an average of 5% each of the total heat production. The cost of protein turnover is the highest energy demanding process. The fact that nitrogen balance becomes positive within 72 hours after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism: dry body mass and fat decrease while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches the statural growth. The goals of the following review are to summarize recent data on the physiological aspects of energy and protein metabolism directly related to the extrauterine adaptation, to describe experimental approaches which recently were adapted to the newborns in order to get "bedside results" and to discuss how far these results can help everyday's neonatal practice.

Adaptation, Physiological↗